The present invention relates to the field of hammers and more particularly to the field of replaceable caps for hammers.
The striking face of a hammer is often subjected to forces that require extra toughness and hardness. Because of the heavy duty usage of certain hammers, the impact faces wear out more rapidly than normal hammers. One example of this type of hammer is the framing hammer, used in the art of house building. Such types of hammer are heavier than the average hammer, and in order to eliminate the cost of a manufacturing an entire hammer that includes a unitary head that meets the toughness required, it is known in the art to attach a separate hammer head portion, or capped head, or cap, at the end area, or pole, of the hammer head. Such caps, which are often made of a strong but heavy metal such as stainless steel, are known in the art.
Hammers have various types of striking faces, for example, flat faces and knurled faces. In addition, hammers having heavy duty striking faces often require different versions of the rear region of the hammer head, for example, a claw and a ball pein. A replaceable cap having a tough striking face thus has another application.
In another area of the art of hammers, shock absorbing structures that reduce shock to the hands and arms of users during impact are known. Combining such shock absorbing structures with a replaceable cap is also known.
Patents relating to the art of hammers that disclose various aspects of capped heads are as follows:
1) Patents that disclose detachable, or replaceable, head caps combined with shock-absorbing cushions or washers known in the art of hammers are as follows:
U.S. Pat. No. 2,518,059 issued to M. Permerl on Aug. 8, 1950, discloses a mallet having interchangeable percussion heads 14 and 17 removably screwed to a mallet head 10. Interposed between the inner end face of percussion members 14 and 17 are washers 16 and 23, respectively, which are made of a resilient material such as rubber.
U.S. Pat. No. 3,000,414 issued to N. Cordis on Sep. 19, 1961, discloses a hammer 10 having a hammer head 12 and a replaceable, or xe2x80x9cfloatingxe2x80x9d, striking head 15 provided with an elongated stud 16 that is accommodated by a bore 17 in hammer head 12. A flexible, resilient sleeve 20 connects floating head 15 to hammer head 12. FIGS. 2-5 show a resilient sleeve 29 that includes a supplemental integral cap 23 providing a rim 24 about striking head 15. Sleeve 20 is capable of withstanding the impact and the constant flexing in its cushioning action. Sleeve 20 also grips the snub-nose tip 14 of hammer head 12 and holds striking head 15 in an alternative embodiment as shown in FIGS. 2-5.
2) A patent disclosing a removable and replaceable capped head is as follows:
U.S. Pat. No. 2,515,431 issued to C. A. Ulfves on Jul. 18, 1950, discloses a unitary detachable hammer tip set forth in FIG. 2 that includes a core 16, a ring 30, and arcuate spring fmgers 24 having reversibly bent gripping elements 26. The entire detachable tip is removably attached to conventional hammer head 10 as shown in FIG. 1.
3) Patents relating to the art of hammers disclosing hammers with cushions or washers or structures for absorbing shock between a separate but non-replaceable cap and the hammer head proper are as follows:
U.S. Pat. No. 1,045,145 issued to E. O. Hubbard on Nov. 26, 1912, discloses a capped hammer head 1 provided with a shock-absorbing rubber cushion 19 for a separate head proper, or cap 10. FIG. 1 shows a cap 10 has a threaded stud 13 screwed into a retaining head 1 mounted inside a sleeve 5 that in turn is threaded onto a reduced threaded portion 4 of head 1. FIGS. 4 and 5 show variations on the particular structure.
U.S. Pat. No. 1,732,985 issued to R. H. Peters on Oct. 22, 1929, discloses a hammer attachment, or cap, including a sleeve 1 and a rubber striking head 7 is secured by clamping means 12 upon a hammer head 15 with a washer 9 fit against a seat 3 connected to striking head 7 positioned within sleeve 1 is described. It is apparent that washer 9 absorbs pressure exerted by hammer head 15.
U.S. Pat. No. 2,198,764, issued to B. E. Edwards on Apr. 30, 1940, discloses a metal working hammer having a hammer head 6 having a floating striking element 11 that is movably secured to a stationary hammer striking element 8 positioned in a cylindrical body portion 12 having a bottom, or strike face 13. A shock-absorbing element, or cushion, 15, is housed in cylindrical body portion 12 between bottom strike face 13 and stationary element 8.
U.S. Pat. No. 2,592,883 issued to C. J. Fisher on Apr. 15, 1952, discloses a hand hammer body 10 having a hammer head 16 with an arcuate hammer face 18. A resilient striking member 22 made of resilient carbon spring steel or similar material is mounted over arcuate face 18 so that a recess is defined between striking member 22 and arcuate face 18. In use, when an indented piece of metal is struck with the hammer, the resilient member 22 will flex inwardly toward the recessed face 18 tending to close the hollow space between face 18 and member 22. Immediately thereafter, the spring action of member 22 with cause the member to flex outwardly again. This inward and outward action imparts a spring-like action and resilience to the hammer head.
U.S. Pat. No. 3,148,716 issued to H. A. Vaughan, Jr. on Sep. 15, 1964, discloses a composite hammer head 10 comprised of a main body portion 11 and an impact tip, or cap 12. The front end face 64 of main body portion 11 forms a socket 62. Impact tip 12 is metallic and includes a striking face 46 and a rear tapered shank 44 press-fitted into socket 62. A washer 66 formed of a shock-absorbing material surrounding the base of shank 44 is interposed between striking head 42 and front end face 64. The combined thickness of washer 66 and the depth of socket 62 is slightly greater than the axial extent of shank 44 so that a sealed air pocket 72 is created in the bottom region of socket 62 absorbs some of the impact that is imparted to impact tip 12.
U.S. Pat. No. 2,884,969 issued to C. M Lay on May 5, 1959, entitled xe2x80x9cHammer Construction with Shock Absorbing Meansxe2x80x9d is cited in U.S. Pat. No. 3,148,176 to Vaughan for the purpose of describing the effects of impact creating vibration effects in the vicinity of the claw region of a carpenter""s claw hammer.
It is an object of the present invention to provide a replaceable cap for a hammer that has a fastening pin that is free of any shearing pressure during the impact stoke of the hammer.
It another object of the present invention to provide a replaceable cap for a hammer that allows a user to replace a cap with one type of striking face with another cap with another type of striking face or to replace the hammer head of a replaceable cap with another type of hammer head, for example, a claw hammer with a ball pein hammer.
It is yet another object of the present invention to provide a replaceable cap for a hammer that has a shock absorbing pad.
It is yet another object of the present invention to provide a replaceable cap for a hammer head that has a pole that is slidably mounted within the chamber of the cap with the pole movable relative to the cap between a static mode and an impact mode and that includes a shock-absorbent pad that is biasable and able to move the pole that has moved from the static mode against the pad toward the cap striking face and is further able to self-biasably return the pole to the static mode with the energy of the self-biasing action being supplied by the energy of the striking action against a workpiece.
It is a further object of this invention to provide a retaining ring for holding the fastening pin for holding the replaceable cap for the hammer head described above.
It is yet another object of this invention to provide an external type of retaining ring for holding the fastening pin described above.
It is yet another object of this invention to provide an internal expansion retaining ring for holding the fasting pin described above.
In accordance with these objects and other objects that will become apparent in the course of this disclosure, there is provided retaining means for holding a fastening cross-pin that holds a removable cap mounted to a pole of a hammer thus providing a selected type of cap impact face for the hammer head. The cap forms a chamber and the pole is removably slidably fitted into the pole chamber. The fastening cross-pin is removably positioned in opposed cap pin holes in the cap cylindrical wall and to a pole pin hole so as to secure the cap to the pole and also so as to allow the pole to move relative to the cap in the longitudinal dimension between an impact mode position of the cap impact face against a workpiece and a static mode position of the cap impact face remote from the workpiece. A biasable pad for absorbing shock is positioned within the chamber formed in the cap between the cap impact face and the pole. The fastening cross-pin extends through the pole pin hole and is connected to the cap side walls. The fastening cross-pin is in contact with the front surface of the pole pin hole in the static mode and moves to a free position in the pole pin hole in the impact mode so that the cross-pin avoids shear during the impact mode. Two types of retaining means are described: one type is an external retaining ring that is set into a groove around the cap that is aligned with both ends of the cross-pin; another type is an internal expansion retaining ring that also the fastening cross-pin that is biased against the pin holes in the cap cylindrical wall.
The present invention will be better understood and the objects and important features, other than those specifically set forth above, will become apparent when consideration is given to the following details and description, which when taken in conjunction with the annexed drawings, describes, illustrates, and shows preferred embodiments or modifications of the present invention and what is presently considered and believed to be the best mode of practice in the principles thereof. Other embodiments or modifications may be suggested to those having the benefit of the teachings therein, and such other embodiments or modifications are intended to be reserved especially as they fall within the scope and spirit of the subjoined claims.